The present invention generally relates to vehicle safety restraint systems, and more particularly to an apparatus and method for accurately sensing the presence and position of an object within the vehicle such that the operating characteristics of the safety restraint system provide maximum passenger protection.
Vehicle safety restraint systems are a well-known means of attempting to reduce the likelihood of serious injury to passengers involved in a vehicle collision. These safety restraint systems include airbags that quickly inflate at the time of a collision in order to prevent the passenger from colliding with fixed objects in the vehicle's passenger compartment, particularly the steering column, dashboard and windshield of the vehicle.
In order to maximize passenger protection during a collision, it is desirable to vary the deployment characteristics of the airbag or operating characteristics of other safety restraint components based on passenger presence and position. Specifically, it is desirable to control factors such as the inflation profile and deployment timing of the airbag depending upon the position of the passenger in a seat (i.e. whether the passenger is "in position" or "out of position").
Vehicle crash conditions may also dictate non-deployment of the airbag. For instance, non-deployment of the airbag may be desirable if the severity of the crash is low and other safety restraint components can provide adequate protection of the passenger (e.g. the seat belt is in use and is sufficient protection in and of itself). In addition, the absence of a passenger in a vehicle seat, an out-of-position passenger, or a child in a child seat all present additional situations in which non-deployment of an airbag or modified deployment is desirable.
It has been shown that an occupant's position can be determined to a limited extent with the use of a single position sensor. The use of a single proximity sensor in order to determine occupant position and presence has several disadvantages. For example, while a single proximity sensor located in the instrument panel (IP) may indicate the distance of an object from the IP, the single sensor cannot distinguish whether a small object (i.e. a hand) is close to the IP or if the torso of the occupant is near the IP. The location of the occupant's torso, as opposed to identification of an "object's" position within a sensor field is advantageous in determining the actions of a vehicle restraint system during a collision.
In view of the foregoing, it is an object of the present invention to provide a system and methodology that accurately determines occupant presence and position for a vehicle safety restraint system that may be subsequently utilized to control the dynamic performance of various safety restraint components in the vehicle so that the actions of these safety restraint components may be controlled in accordance with the occupant's seating position and severity of an accident in order to maximize passenger protection in a vehicle collision. Additional advantages and features of the present invention will become apparent from the subsequent description and appended claims, taken in conjunction with the accompanying drawings.
In accordance with the teachings of the present invention, an occupant sensing apparatus for controlling operating characteristics of a vehicle's safety restraint system is provided. The apparatus has a first proximity sensor emitting a first field, forming a first zone, in a first direction and generating a first output signal indicative of the relative position of the occupant to the first sensor, and a second proximity sensor emitting a second field forming a second zone, in an opposite second direction that is substantially towards the first field and generating a second output signal indicative of the relative position of the occupant to the second sensor. A controller receives the first and second output signals and generates a control signal that is used to control the operating characteristics of the vehicle's safety restraint system.